Passive dosing dispensers for toilets are in evidence in prior patents. For instance, U.S. Pat. No. 3,908,209, which was issued to William E. Fillmore on Sept. 30, 1975, discloses a means for dispensing fluid into a tank as the water recedes by means of a float valve, which allows the dispenser to be open while the water recedes from level A to level B. However, the cost of using a liquid additive is relatively high because of the weight and the subsequent difficulty in handling. Therefore, a more desirable dispenser would allow for the dissolution of a dry tablet additive. U.S. Pat. No. 4,186,856, which was issued to Robert S. Dirksing on Feb. 5, 1980, provides a passive means for dispensing a dry additive in solution. However, the Dirksing invention does not provide complete separation of the additive solution from the tank water.
Most recently, U.S. Pat. No. 4,307,474, which was issued to Clement K. Choy on Dec. 29, 1981, provides a means for separating the additive from the tank water; however, it does not provide for rapid discharge of the solution. The failure to discharge the dispenser rapidly results in the container not completely discharging before the tank starts to refill and, therefore, the dose of additive supplied to the tank is incorrect.